The Third World Congress on Pain, sponsored by the International Association for the Study of Pain (IASP) will be held in Edinburgh, Scotland, UK on September 4-11, 1981 (registration and scientific sessions, September 6-11, 1981). Like the First World Congress on Pain held in Florence, Italy in 1975 and the Second World Congress on Pain held in Montreal in 1978, the goals and objectives of this Congress are to bring together scientists, physicians, dentists, and other health professionals from various parts of the world, representing virtually every basic science and clinical discipline, to report new information and reappraise current knowledge on pain mechanisms and various therapeutic modalities in current use. The scientific program of the Congress will include five plenary (single track) sessions, breakfast and lunch sessions, workshops, and free communications. The workshop on "Cancer pain: updata on mechanisms and therapy", as well as several other workshops and breakfast sessions, will deal directly with the area of research on cancer pain of primary interest to NCI. In addition, all of the plenary sessions and lectures will include consideration of basic mechanisms and principles of diagnosis and therapy which apply to acute and chronic pain and especially cancer pain. Based on our experiences of the previous two world congresses, it is anticipated that: (1) over 1200 biomedical scientists and health professionals, representing every basic science and clinical discipline from over 40 countries in the world will attend the Third World Congress on Pain; (2) about 450 presentations will be made; (3) the Congress will enhance interaction, communication, and cross-fertilization among the participants of different disciplines; and (4) it will greatly facilitate the rapid application fo new knowledge to the diagnosis and treatment of acute and chronic pain. Moreover, the Congress should help define more clearly the needs and directions of future research efforts and provide opportunities for collaborative interdisciplinary study and treatment of acute and chronic pain. The ultimate goal is to help improve the care of patients with acute and chronic pain, which currently constitute a major national and world health and economic problem.